The present invention relates generally to a method and system for energy conversion and relates more specifically to a method and system for energy conversion using a screen-free-electron source.
While working on the invention of the incandescent light bulb, Thomas Edison observed that a current flowed between the hot filament of a bulb and a nearby metal plate, and that the current abated over time, eventually falling to zero. He further noted that the current would return if a small voltage were applied between the plate and filament, with the current abating as before when that voltage was removed. Although the current was eventually recognized as a flow of free electrons between the filament and plate, the current abatement was anomalous when compared with expectations for a current of electrons experiencing a Coulomb interaction. Free electrons expelled from the cathode surface have a standard Maxwell-Boltzmann exponential thermal energy distribution, and the electrical potential produced by the free electrons would necessarily have a minimum between the filament and palte that would act as a barrier to the free-electron flow. An increase in the magnitude of the potential minimum by 70% would be required to halve the current flow, resulting in a consequent 70% increase in the expelling force experienced by the electrons outside of that minimum. With the cathode current unchanged and the free-electron expulsion rate nearly doubled, the charge buildup that led to the potential increase would become depleted nearly instantaneously, correcting the buildup. The return of the current following the introduction of an external voltage implies that the abatement is due to a space charge or electron cloud that forms around the cathode, but that cloud buildup would be forbidden unless the electrical field of the free electrons were diminished or screened. Such screening of a free-electron source is used in embodiments of the invention.
Embodiments of the invention provide a method and device for providing power to a load. A beam of free electrons is directed from a free-electron source, such as an electron gun, into an enclosing conductive surface. The free-electron source includes a cathode, which is maintained at a negative voltage with respect to the enclosing conductive surface. A region around the free-electron source is maintained in a vacuum. The system is configured to switch over a time period between two configurations. In the first configuration, the enclosing conductive surface is isolated from ground. In the second configuration, the enclosing conductive surface is in electrical communication with ground. Capacitive energy is discharged from the enclosing conductive surface when in the second configuration with an electrical circuit arrangement and provided to the load.
In some embodiments the cathode is a hot cathode, while in other embodiments it is a cold cathode. In one embodiment, the electrical circuit arrangement includes a diode and a capacitor. In another embodiment, the electrical circuit arrangement includes a capacitor and an inductor configured to provide current oscillations. In a further embodiment, the beam of free electrons is constrained magnetically so that its trajectory ensures the free electrons travel to an end of the enclosing conductive surface opposite the free-electron source before contacting the enclosing conductive surface. The free electrons may be temporarily interned in a magnetic bottle. The magnetic bottle may be provided by a pair of aligned permanent magnets. In certain embodiments, the beam of electrons is derived from a cloud of electrons that may be formed. Directing the beam of electrons may include providing a flow of gas, such as a flow of inert gas, from the free-electron source towards an end of the enclosing conductive surface. In a particular embodiment, directing the beam of electrons includes slowing the electrons.
In some embodiments, a conducting grid is included in electrical communication with the enclosing conductive surface to prevent charges from the enclosing conductive surface from being drawn into the free-electron source. In one such embodiment, the conducting grid and the cathode are hemispherical.
In another embodiment, the enclosing conductive surface comprises a plurality of conductive subenclosures housed within a nonconducting vacuum enclosure, each of the subenclosures being shielded from other subenclosures. The beam of free electrons is successivly deflected into the conductive subenclosures over the time period. In some embodiments, the beam of free electrons may be focused, such as by providing a plurality of electron guns configured to direct the beam of free electrons through a confined region.